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| Titel |
Ozone decomposition on Saharan dust: an experimental investigation |
| VerfasserIn |
F. Hanisch, J. N. Crowley |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 3, no. 1 ; Nr. 3, no. 1 (2003-02-11), S.119-130 |
| Datensatznummer |
250000714
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| Publikation (Nr.) |
 copernicus.org/acp-3-119-2003.pdf |
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| Zusammenfassung |
| The heterogeneous reaction between
O3 and authentic Saharan dust surfaces was investigated in a Knudsen reactor at
approx 296 K. O3
was destroyed on the dust surface and
O2
was formed with conversion efficiencies of 1.0 and 1.3 molecules O2
per O3
molecule destroyed for
unheated and heated samples, respectively. No O3
desorbed from exposed dust samples,
showing that the uptake was irreversible. The uptake coefficients for the irreversible
destruction of O3
on (unheated) Saharan dust surfaces depended on the
O3
concentration and
varied between 3.5 x 10-4 and 5.5 x 10-6 for the initial uptake coefficient
(g0
approx 3 x 10-5 at 30 ppbv O3
STP) and between
4.8 x 10-5 and 2.2 x 10-6 for the steady-state uptake coefficient
(gss
approx 7 x10-6 at 30 ppbv O3
STP). At very high
O3
concentrations the surface was deactivated,
and O3
uptake ceased after a certain exposure period. Sample re-activation
(i.e. de-passivation) was found to occur over periods of hours, after exposure to
O3
had ceased,
suggesting that re-activation processes play a role both in the laboratory and in the atmosphere. |
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